A. The Prior Art
Most prior art deadbolt door locking devices are either external (in the sense that they are mounted on the inside of, but external to the door) or internal (in the sense that they are mounted within the door. Because internal locks are tunnelled into wooden doors, thereby weakening the lock by as much as 75%, external deadbolt locks serve a very important function as secondary reinforcing locks. Moreover, since many internal deadbolt locks can be opened from the outside by key, external deadbolt locks are also used to prevent access by lock picking or in places where keys may not be strictly controlled.
When external deadbolts are so used as the ultimate security measure it is especially important that they are simple to operate and easily and safely coordinated with identification guards, even by those who may be incapacitated, ill or half asleep. Prior art chain guards, besides being cumbersome and dangerous to operate, hazarding the fingers of children cannot be easily coordinated with a lock. Bracket type guards present the same problem. To use one with the other may take some skill, concentration, or even more than two hands. For example, to use a conventional chain guard in conjunction with a conventional deadbolt lock, one must unhang, then rehang the end of the chain; then retract the deadbolt (one or two movements); then turn the door knob and crack the door)--six movements all in proper sequence.
It would therefore be an advance in the art if an effective deadbolt lock were so combined with a guard that only two movements were required (one with each hand) to safely crack the door.
It is therefore an object of this invention to provide a deadbolt lock/guard combination which minimizes the movements and coordination required to safely crack the door.
It is another object of this invention to provide an external deadbolt lock with improved co-planar stability which is especially useful with double doors.
It is yet another object of this invention to provide an external deadbolt lock which is virtually tamperproof with wire.
B. Brief Description of the Invention
These and other objects are accomplished in a guarded deadbolt lock comprising in combination a sliding bolt assembly with an essentially U-shaped sliding bolt, the bend and contiguous portion being the lock engagement portion, and the ends and contiguous portion being the squeeze-type handle portion. The bolt slides in a channel which has a channel closure means to hold the bolt in the channel and mounting means for the channel.
Juxtaposed with the bolt assembly is a channel shaped receiver assembly for receiving the bolt, which also has closure means and mounting means.
Hinge-mounted on either assembly is an elongated guard with an elongated hook. This hook fits over and engages the channel closure means of the other assembly (preferably with a point of resistance to prevent accidental disengagement), in one position, and in a second position lies disengaged but preferably retained in the channel in which mounted, the guard fitting easily between the legs of the sliding bolt as necessary to assume either of these positions.